Spark-plug.



A. l. CHAMPION.

SPARK PLUG.

APPLICATION FILED JUNE 4,1917.

Patented Apr. 16, 1918.

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nests-no Application filed 2i To all? whom may concern:

Be 1t known that l, .lLBERT J, CHAMPION, a cltlzen of the Republic of France, residing at Flint, in the county or Grenesee and State with;

intense heat, it is very essential to prov or" Michigan, have, invented certain new Figs. 2, 3 and are cross-sections planes 22, 33 and respectively:

In the construction of spark-plugs whiclare designed for use with high-speed gines or in other places where subjected 'l adequate means for dissipating the from the insulator and electrode therethrough, the electrode being rnaoie of metal having a high rate or thermal con ductivity, and it is desirahle to restrict the area which is exposed to the coinhusticn heat, itself forms a means for dissipating the heat which is imparted to the insulator, and for this purpose a large cross-section ad vantageous. l have therefore devised a con: struction of electrode and cci'iperating irrsulator in which the inner or exposed end oi the electrode is oi relatively small crosssection, and the cross-section of the out wardly-extending shank portion is pro= gressively increased. The insulator is correspondingly fashioned, being provided with a small hore at'its inner end for receiving the small end of the electrode and a series or Specification of Letters 0n the other hand, this electrode Patented npro is,

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enlarged hores or counter-bores for receiving; the corresponding portions of the electrode,

in detail, A is an insulator formed or any suitable material and adapted for mounting in a metallic casing of any suitable construction (not shown). fhis insulator is formed with a srnall bore at its inner end, which extends through the inwardly-projecting portion thereof portion D of the insulator, which is of larger diameter and is subjected to the clamping" stresses of the casing The bore E is of increased diameter, while the outwardlyproiecting portion of the insulator has a arger bore The electrode ll is pro C with portions 1, d and for respecttin the horse B, E and the construction described, when the plug is in use and subjected to high nca he small section l of the electrode will restrict the amount of heat conducted therethroug'h, w is the successively larger crosssections oi the electrode are useful in more rapids dissipating heat from hoth the en posse. portion of the electrode and from the insul tor itself. The advantage of having series of steps instead of a single enlargement is that the insulator is stronger mechanically and is also subjected to more gradual temperaturechanges, which lessen the tendency to fracture.

i claim as my invention is: a spark-plug, the combination of an insulator having" a small sized bore through the inwardlyprojecting portion thereof, an enlarged here throughdae enlarged central or body portion and a further enlarged bore through the'outwardlv-entending portion, and an electrode having port ons of corresponding size for fitting wlthin sa1d hisulator In testimony whereof I afix my slgnature.

ALBERT J. GHAMPIQN.

in the central or body 

